Marriage madness is in the air, fantasy politics from the dottier forces of conservatism. Of course, schools can't teach children to get married, nor can governments prod unwilling adults to the altar. Campaigners for financial marriage incentives bizarrely believe that people entering ruinous divorces - losing their homes and a large slice of income - will suddenly change their minds if offered a puny marriage allowance.

But there is one thing the government is about to do which might just help some parents stay together. Gordon Brown is about to redistribute large sums of money from fathers to mothers in a wallet to handbag transfer. It was whispered in one short line in his last budget and it will emerge in full in next month's, though probably not spun in quite those terms. (Governments have always been uneasy about overtly taking from men to give to women.)

Here's the story. Arm sharply twisted by a caucus of Tory female high flyers, Nigel Lawson reluctantly brought in women's independent taxation. Households would no longer be taxed together, but each partner would be treated separately. It made a great many already well off couples a great deal richer. It was bonanza time in households with two high taxpayers, widening the wealth gap between haves and have-nots in a country increasingly divided between two-earner and no-earner families. Rich women's politics triumphed over class politics - a mistake, but now probably irreversible.

This liberation from tax was not much use to poor women who earn too little to pay any or to women on benefits. The social security system stayed unreformed, treating women in couples as men's chattels. After computing the incomes of both partners and the number and ages of children, all entitlements are paid to the man. The mother has no independent right (except in rare cases where she's nominated instead). The giro goes to the father, stepfather or to a male cohabitee (any man who stays three nights a week).

What effect does that have on poor families on benefit? It explains why they divorce and separate in far higher numbers than the better off. A woman on her own with her children claims all the benefits, including rent and council tax. Where women control the purse strings, research shows they spend far more on the household, food and children than when men control the money. Research on divorcing women living on benefits shows how much richer they feel once they control all their own money. Men who keep more than a very small sum from the family benefit giro can leave women and children virtually destitute. Those worried about saving marriages have had nothing to say about a system which obliged many mothers to abandon men in order to feed their children.

In justice, poor women should have had the same financial liberation as well-off women, with a benefits system as blind to their cohabiting arrangements as the tax system now is. But disaggregating family incomes on social security would be phenomenally expensive: the tax bonus rich couples got from the state was welcomed, but a similar windfall for the poor would be politically unacceptable because it would be a new work disincentive. However, the chancellor is about to do the second best thing: family income will still be computed together but the mother will for the first time collect all the entitlement for herself and her children. Her partner will only collect his own personal allowance. Since all the growth in the social security system is to be increasingly piled onto the new integrated children's credit, most family money will rest in the far safer hands of mothers. It will put right the mistake made when family credit (paid to mothers) was ditched in favour of working family's tax credit (paid into men's pay packets for couples).

A joint treasury and social security committee has been working out how to combine tax and benefits - something that should have been done 50 years ago. By 2003 the new working family tax credit will have been abolished in favour of a far more subtle and finely tuned mechanism designed to eliminate the big barrier preventing parents taking jobs. Integrated child credit will be a completely secure and permanent cushion to support poorer children. It will not vary when either parent moves in or out of work. It will iron out the glitches that make parents, especially single mothers, afraid to take a job for fear of weeks without benefit if the job fails. It's a kind of junior citizens income, but neatly targeted at lower earners, making it worth risking a temporary job - the best route to a permanent one - by keeping families afloat through bumpy times.

Will this achieve Labour's promise to abolish child poverty? It's a well-honed silver chute to pour money straight to poor children, but it depends how much money goes down it. Abolishing poverty isn't just a matter of direct funds but how much money goes to all the other poverty-busting schemes. Will the economy and employment stay buoyant? Will schools turn out no more future parents doomed to fail? Sure Start, for babies at risk, must work and it may take 10 years before we know if Blunkett's babies will succeed. Ending poverty remains a breathtakingly ambitious endeavour.

It depends most of all on creating a long-term public will to do it. So far Labour has not done much to persuade the electorate what public money can do in these times of affluence. There is a limit to how much money can go to children through social security if Labour keeps promising to cut the DSS budget. Increasing it might be a better boast. But just as they tax by stealth, so far they have been paying out by stealth too: all Brown's generous new benefits have been relabelled as tax credits and no longer appear on the DSS budget but are hidden away in inland revenue accounts. It won't work. The Daily Mail and the Tories will insist on counting these into the overall social security bill. In the end, just as you need sustainable economic growth, so you also need sustainable public support for what you are doing. Not enough money can be stealthily spent on poverty programmes: the public has to be proud of what is being done in its name.

That is the big question for the next election. Labour has the Tories skewered on their daft low tax pledge: Hague's tax guarantee is easily bounced back as the Tory cuts guarantee. But Labour needs to say publicly that more spending, a lot more, is required. That will mean more taxing, which requires people to be persuaded that well-spent tax pounds can buy richer things than the pounds in their pocket. The first place to begin is with national insurance contributions: this is the budget to remove the NI artificial ceiling which allows the rich to pay a smaller share of their income than everyone else. It would raise a splendid £4.8bn - serious money to put towards that difficult, multi-faceted poverty pledge.